Synchronisation helps unlock full potential of AI

Ian Knight, who runs a spring-calving beef herd in Cumbria, had previously shunned artificial insemination because he believed it would be too challenging to spot animals in heat.

However, when it became uneconomic to buy top-quality bulls for his commercial herd, he was prompted to revisit the option. And by implementing a synchronisation programme, he has been able to take full advantage of the benefits of AI.

Making the decision

“I have cattle here, there and everywhere, so I knew the best approach would be to synchronise them to come into heat at a given time,” says Mr Knight, who farms at Calderbridge, west Cumbria.

“It meant I didn’t have the time commitment and expense of watching cows for five weeks and I could put all the animals through the system in one go.”

Working with his vet Chris Harrison, of West Lakes Veterinary Group, he used an oestrus synchronisation programme on 30 cows last year and was surprised by the results. “Some 78% held to first service, although the vet thought this was probably a one-off,” Mr Knight recalls.

On average, first service AI pregnancy rates of 65% or higher can be achieved, but only with good nutritional management, control of diseases that influence fertility and attention to detail.

Mr Knight used synchronised AI on 67 cows and 25 heifers to calve this spring, with semen from five different bulls. “The beauty of AI is that you can chop and change the bulls you use,” he says.

He had previously run bulls with the herd of British Blue and Limousin crosses, but as margins in commercial beef production have narrowed, he felt unable to justify investing in top-quality bulls.

The costs

“I went to a sale in Carlisle and the bulls I was interested in ranged from £14,000-17,000. When I sat down to look at the figures it just wasn’t viable. At that price every calf the bulls produced had to be a show winner. I realised the only option I had was to use top genetics through AI; it meant I could still invest in good bulls.

“The vet costs and products are £21.30 excluding VAT for every animal and it averages £15-20 a cow for two straws of semen and £8 for two straws of semen for each heifer.”

Gareth Scott, beef sales manager at Cogent, says semen from bulls with leading traits is readily available at less than £20 a straw. The figures, he believes, make financial sense when compared to buying a bull.

AI versus natural service

“A farmer might spend £10,000 on a new bull, but it might not suit the herd. It would therefore be a huge investment to produce something that isn’t quite right. With AI, you can try a bull on a few selected animals first,” he explains.

He calculates it costs £228 to produce a calf from a bull that costs £30,000 over its lifetime. This figure takes into account feed, vet fees, labour and insurance for a bull inseminating 40 cows a season, over four seasons, and achieving a 95% conception result.

Mr Scott compares this to AI at £42 a calf, a figure he says would be achieved in a herd that uses an average of 1.5 straws to attain a 90% conception rate, factoring in a technician’s fee of £15 a cow.

Mr Scott says synchronising AI enhances these cost benefits by tightening the calving period. Calves produced in the first 10 days of the calving period achieve optimum growth.

Choosing synchronisation

“If an animal is growing at 0.4kg a day and has an additional 20 days of growing compared with calves born at the end of the calving period that is an extra 28kg of growth. At around £2.50/kg it’s a big financial gain,” says Mr Scott.

Synchronisation also makes AI convenient, he adds. “If beef cattle are some distance from the farm, a farmer wouldn’t be in a position to monitor them for signs of bulling.”

But one of the downsides is that animals have to be handled a minimum of three times and research suggests synchronisation does not improve cow fertility.

Mr Knight inseminates heifers and cows twice. “For the cost of an extra straw of semen it is worth doing the double insemination to get that hit,” he believes.

The synchronisation programme is as follows:

On day one his vet inserts a progesterone releasing device into the cow’s vagina and administers 2.5ml of a synthetic releasing hormone analogue for both the luteinising and follicle-stimulating hormones.

On day seven animals are injected with prostaglandin.

The progesterone-releasing device is removed on the morning of day nine and 400iu of PMSG (Gonadotrophin) injected.

The first service takes place on the morning of the 11th day and the second insemination on the morning of the 12th day.

Mr Knight checks for signs of heat on day 33 and AIs any animals seen bulling on days 34 and 35.

To achieve the best results, cows should ideally have calved at least 40 days before entering a synchronisation programme. Any less and they are not as likely to be cycling at the time implants are inserted. Even though progesterone-based programmes will bring most cows out of anoestrus, pregnancy rates from the first post-calving heat may be poor.

Mr Knight opted for maternal bulls this year, but with an emphasis on a good beef index to capitalise on the value of any male calves born.

Key considerations

His advice to farmers considering a similar approach to insemination is to invest in a good handling system. He initially loaned a mobile handling system from a neighbour, but now has his own.

“By the time the vet has done the injection and you do the AI the animals have been through the crush six times, and they have young calves at foot, which makes handling even more of a challenge. There is a lot of work involved. For us it is the only option though.”

Mr Scott believes AI with the added advantage of synchronisation is relevant to all beef systems. “Some farmers might want to breed replacements or animals for particular shows and others whole herds, it shouldn’t exclude anyone,” he said.

“My advice to farmers would be to step out of the box and examine how synchronised AI can fit into their systems. We can all get boxed into our way of thinking, it is good to sit back and explore the alternatives.”